A heterojunction bipolar transistor is provided having an improved current gain cutoff frequency. The heterojunction bipolar transistor includes a contact region formed from InGaAsSb. The contact region allows an emitter region of the heterojunction bipolar transistor to realize a lower contact resistance value to yield an improved cutoff frequency (fT).
|
18. A heterojunction bipolar transistor, comprising
a substrate; a collector portion having at least one layer of a first material; a base portion having at least one layer of a second material; an emitter portion having at least one layer of a third material; and a contact having at least one layer of said first material and at least one layer of a InxGa1-x(As1-ySby) (0<x<0.7) (0<y<0.5) material.
1. A heterojunction bipolar transistor, comprising
a substrate; a collector portion having at least one layer of a first material; a base portion having at least one layer of a second material; an emitter portion having at least one layer of said first material; and a contact portion having at least one layer of said first material and at least one layer of an InxGa1-x(As1-ySby) (0<x<0.7) (0<y<0.5).
40. A method for forming a compound semiconductor device, the method comprising the steps of:
forming a collector stack having at least one layer of a first material on a substrate; forming a base stack having at least one layer of a second material on a portion of the collector stack; forming an emitter stack having at least one layer of a third material on a portion of the base stack; and forming a contact stack on a portion of the emitter stack, the contact stack having at least one layer of said first material and at least one layer of an InxGa1-x(As1-ySby) (0<x<0.7) (0<y<0.5) material.
35. A method for forming a compound semiconductor device, the method comprising the steps of:
forming a collector stack having at least one layer of a first material on a substrate; forming a base stack having at least one layer of a second material on a portion of the collector stack; forming an emitter stack having at least one layer of said first material on a portion of the base stack; and forming a contact stack on a portion of the emitter stack, the contact stack having at least one layer of said first material and at least one layer of an InxGa1-x(As1-ySby) (0<x<0.7) (0<y<0.5) material.
2. The heterojunction bipolar transistor of
3. The heterojunction bipolar transistor of
5. The heterojunction bipolar transistor of
6. The heterojunction bipolar transistor of
7. The heterojunction bipolar transistor of
8. The heterojunction bipolar transistor of
9. The heterojunction bipolar transistor of
10. The heterojunction bipolar transistor of
11. The heterojunction bipolar transistor of
12. The heterojunction bipolar transistor of
13. The heterojunction bipolar transistor of
14. The heterojunction bipolar transistor of
15. The heterojunction bipolar transistor of
16. The heterojunction bipolar transistor of
17. The heterojunction bipolar transistor of
19. The heterojunction bipolar transistor of
20. The heterojunction bipolar transistor of
22. The heterojunction bipolar transistor of
23. The heterojunction bipolar transistor of
24. The heterojunction bipolar transistor of
25. The heterojunction bipolar transistor of
26. The heterojunction bipolar transistor of
27. The heterojunction bipolar transistor of
28. The heterojunction bipolar transistor of
29. The heterojunction bipolar transistor of
30. The heterojunction bipolar transistor of
31. The heterojunction bipolar transistor of
32. The heterojunction bipolar transistor of
33. The heterojunction bipolar transistor of
34. The heterojunction bipolar transistor of
36. The method of
39. The method of
41. The method of
44. The method of
|
|||||||||||||||||||||||||||
This application claims priority to U.S. provisional application Serial No. 60/306,833, filed on Jul. 20, 2001, and entitled Low Emitter Resistance Contacts to InP High Speed HBT.
This invention relates generally to semiconductor transistors. In particular, the invention relates to heterojunction bipolar transistors. Heterojunction bipolar transistors (HBTs) offer much higher speed of operation than the more prevalent metal-oxide-semiconductor field-effect transistors (MOSFETs) or even conventional homojunction bipolar transistors, e.g., pnp or npn silicon transistors. Because HBTs offer high speed, a high current driving capability, and a low 1/f noise levels, HBTs are becoming popular for use as integrated switching devices and microwave devices in wireless communications systems and sub-systems, satellite broadcast systems, automobile collision avoidance systems, global positioning systems, and other high-frequency applications. One application in which HBT use continues to increase is in the design and manufacture of wireless electronic devices, such as wireless telephones and other like electronic devices that are capable of communicating with a network in a wireless manner. Although HBT's offer many benefits over bipolar silicon transistors, there remains a need to improve or extend the frequency response of HBT's.
The present invention provides an GaAs based HBT having an increased or extended frequency response. The GaAs based HBT provides an improved frequency response by reducing an emitter resistance value of the HBT.
In one embodiment of the present invention, a heterojunction bipolar transistor is provided that includes a substrate, a collector portion having at least one layer of a first material disposed on the substrate to form a first stack, a base portion having at least one layer of a second material disposed on a portion of the collector portion to form a second stack. The HBT further includes an emitter portion having at least one layer of the first material disposed over a portion of the base portion to form a third stack and a contact portion having at least one layer of the first material and at least one layer of an InxGa1-x(As1-ySby) (0<x<0.7) (0<y<0.5) material disposed over a portion of the emitter portion to form a fourth stack. The InxGa1-x(As1-ySby) (0<x<0.7) (0<y<0.5) material of the contact portion and the first material of the contact portion provide a minimal conduction band offset in the contact region of the HBT, when compared to other material types. As such, a conduction band discontinuity between in the contact region is minimized to improve the flow of electrons between the contact region and the emitter region, and, as such, realizes a reduction in the resistance value of the emitter region. The reduced resistance value of the emitter significantly increases the frequency response of the HBT. As such, the current gain cutoff frequency (fT) of the HBT is improved above 200 GHz.
In another embodiment of the present invention, a heterojunction bipolar transistor is provided that includes a substrate, a collector portion having at least one layer of a first material disposed on the substrate to form a first stack, a base portion having at least one layer of a second material disposed on a portion of the collector portion to form a second stack. The HBT further includes an emitter portion having at least one layer of a third material disposed over a portion of the base portion to form a third stack and a contact portion having at least one layer of the first material and at least one layer of an InxGa1-x(As1-ySby) (0<x<0.7) (0<y<0.5) material disposed over a portion of the emitter portion to form a fourth stack. The InxGa1-x(As1-ySby) (0<x<0.7) (0<y<0.5) of the contact portion and the first material of the contact portion provide a minimal conduction band offset in the contact region of the HBT, when compared to other material types. As such, a conduction band discontinuity in the contact region is minimized to improve the flow of electrons between the emitter region and the contact region, and as such, reduce the resistance value of the emitter region. The reduced resistance value realized by the emitter significantly increases the frequency response of the HBT. As such, the current gain cutoff frequency (fT) of the HBT is improved above 100 GHz.
In still another embodiment of the present invention a method for forming a compound semiconductor device having an extended frequency response is provided. The method includes steps for forming a collector stack having at least one layer of a first material on a substrate and forming a base stack having at least one layer of a second material on a portion of the collector stack. The method further provides the steps for forming an emitter stack having at least one layer of the first material on a portion of the base stack, and forming a contact stack having at least one layer of the first material and at least one layer of an InxGa1-x(As1-ySby) (0<x<0.7) (0<y<0.5) material on a portion of the emitter stack. The forming of the contact stack of the InxGa1-x(As1-ySby) (0<x<0.7) (0<y<0.5) material and first material allows the fabricated compound semiconductor device to realize a significant reduction in emitter resistance due to a minimal conduction band offset value in the contact stack. The resulting compound semiconductor device realizes an improved or extended fT of about 100 GHz.
In yet another embodiment of the present invention a method for forming a compound semiconductor device having an extended frequency response is provided. The method includes steps for forming a collector stack having at least one layer of a first material on a substrate and forming a base stack having at least one layer of a second material on a portion of the collector stack. The method further provides the steps for forming an emitter stack having at least one layer of a third material on a portion of the base stack, and forming a contact stack having at least one layer of the first material and at least one layer of an InxGa1-x(As1-ySby) (0<x<0.7) (0<y<0.5) material on a portion of the emitter stack. The forming of the contact stack of the InxGa1-x(As1-ySby) (0<x<0.7) (0<y<0.5) material and the first material allows the fabricated compound semiconductor device to realize a significant reduction in emitter resistance due to a minimal conduction band offset value in the contact stack. The resulting compound semiconductor device realizes an improved or extended fT greater than 100 GHz.
The foregoing and other objects, features and advantages of the invention will be apparent from the following description, and from the accompanying drawings, in which like reference characters refer to the same parts throughout the different views. The drawings illustrate principles of the invention and are not to scale.
The compound semiconductor of the present invention employs a contact region in communication with an emitter region to allow the compound semiconductor device to realize an improved or extended frequency response. The fT realized by the compound semiconductor device extends or improves the frequency response of the device to about 100 G Hz. The improved cutoff frequency of the compound semiconductor is particularly suitable for applications where the compound semiconductor device operates as part of a clock data recovery circuit, as a multiplexer circuit or part of a multiplexer circuit, as a transimpedance amplifier, or as a laser driver. Specifically, each of the illustrative embodiments described below are directed to GaAs based HBT device for use in portable or mobile electronic devices, such as cellular telephones, laptop computers with wireless modems and other like portable consumer devices, or other wireless communication devices and systems, such as satellite systems, terrestrial based systems, or a hybrid of terrestrial and satellite based systems. The compound semiconductor device of the present invention is configurable to suit a selected application as illustrated in the exemplary embodiments described in more detail below.
The compound semiconductor device of the present invention provides a range of significant benefits to engineers that design electronic devices capable of communicating with a network in a wireless manner. The compound semiconductor device of the present invention can extend or increase the cutoff frequency of the electronic device that communicates with a network in a wireless manner to provide the device or network with an improved bandwidth. The compound semiconductor device of the present invention is able to improve or extend the fT of an GaAs HBT to greater than 100 GHz. In this manner, the GaAs HBT of the present invention is well suited for applications that benefit from a device with a high switching speed, for example a multiplexer, a clock and data recovery circuit, or other like high speed operation.
In more detail, the sub-collector layer 12 is a GaAs material formed over an GaAs substrate 11 and has a thickness of about 500 nm with an n-type impurity concentration of about 4×1018 cm-3. The thickness of the sub-collector layer 12 can be incrementally changed in 1 nm increments in a range from between about 500 nm and about 1,500 nm to reach a desired value. The collector layer 14 is formed over a portion of the sub-collector layer 12. The formed GaAs material of the collector layer 14 has a thickness of about 300 nm and is doped to have an n-type impurity concentration of about 1×1016 cm-3. The collector layer 14 can have its thickness incrementally changed in 1 nm increments in a range from between about 100 nm and about 2000 nm to reach a desired thickness.
The base layer 16 is a GaAs material formed over a portion of the collector layer 14 and is formed to have a thickness of less than about 50 nm. The base layer 16 is doped with p+ impurities to have a high impurity concentration of about 4×1019 cm-3. It is further desirable to form the base layer 16 to have a thickness of between about 20 nm and about 40 nm. The thickness of the base layer 16 can be incrementally changed in 1 nm increments across the range of thickness to reach a desired value. The impurity concentration in the base layer can range from 1×1019 t0 1×1020 cm-3.
The emitter layer 18 is formed of an AlxGa1-xAs (0<x<0.5) material over a portion of the base layer 16. The emitter layer 18 is doped with N+ impurities in a concentration of about 3×1017 cm-3. The emitter layer 18 is formed to have a thickness of about 50 nm, but can have a thickness of between about 10 nm and about 200 nm. The thickness of the emitter layer 18 can be incrementally changed in 1 nm increments across the thickness range to reach a desired thickness value.
The contact 20 is an GaAs material doped with N type impurities in a high concentration of about 4×1018 cm-3. The contact 20 is formed to have a thickness of about 100 nm and is formed over a portion of the emitter layer 18. The thickness of the contact 20 can range from between about 50 nm to about 300 nm in 1 nm increments.
The contact layer 22, is formed from an InxGa1-x(As1-ySby) (0<x<0.7) (0<y<0.5) material doped with N+ type impurities in a high concentration in excess of 1×1019 cm-3. The contact layer 22 is formed to have a thickness of between about 30 nm and about 150 nm, and is formed over a portion of the contact 20. The thickness of the contact layer 22 can range from between about 30 nm and about 150 nm in increments of 1 nm.
The contact layer 22 formed from the material and the contact 20 formed of the GaAs material provides a significant reduction in an emitter resistance value. The minimal conduction band offset or discontinuity between the InxGa1-x(As1-ySby) (0<x<0.7) (0<y<0.5) material and the GaAs material that form the contact portion of the HBT 10 allow the emitter portion of the HBT 10 to realize a significant reduction in an emitter resistance value. For example, the emitter of the HBT 10 realizes an emitter resistance value of between about 3 ohms and about 7 ohms (L=2×2 um2). The contact portion of the HBT 10 can be doped with a variety of n-type dopants, for example, silicon, tellurium, sulfur, tin, or selenium to realize a lower emitter resistance. Moreover, the use of indium in the contact portion of the HBT 10 provides an increase in the electron mobility, which, in turn, provides a reduction in the resistance value associated with the emitter portion of the HBT 10. As such, the HBT 10 is well suited for use in or as a high speed multiplexer or in a high speed clock or data recovery circuit.
In more detail, the substrate is an GaAs material. The sub-collector layer 52 is an InP material formed over the substrate 41 and has a thickness of about 500 nm with an n-type impurity concentration of about 4×1018 cm-3. The sub-collector layer 52 can have a thickness from between about 500 nm to about 1,500 nm. The thickness of the sub-collector layer 52 can be changed in increments of about 1 nm. The collector layer 44 is formed of an GaAs material over a portion of the sub-collector layer 52. The formed GaAs material of the collector layer 44 has a thickness of about 300 nm and is doped with an n-type impurity concentration of about 1×1016 cm-3. The collector layer 44 can have its thickness changed in 1 nm increments in a range from between about 100 nm to about 2,000 nm.
The base layer 46 is a p-type GaAs material formed over a portion of the collector layer 44, and is formed to have a thickness of less than about 40 nm. The base layer 46 is doped to have an acceptor impurity concentration of about 4×1019 cm-3. It is further desirable to form the base layer 46 to have a thickness of between about 20 nm and about 40 nm. The thickness of the base layer 46 can be changed in increments of 1 nm. The impurity concentration in the base layer can range from 1×1019 t0 1×1020 cm-3.
The emitter layer 48 is formed of an In0.51Ga0.49P material over a portion of the base layer 46. The emitter layer 48 is doped with N type impurities in a concentration of about 3×1017 cm-3. The emitter layer 48 is formed to have a thickness of between about 50 nm to about 300 nm in 1 nm increments. It is desirable to form the emitter layer 48 with a thickness of about 50 nm.
The contact 50 is an GaAs material doped with N+ type impurities in a high concentration of about 4×1018 cm-3. The contact 50 is formed to have a thickness of between about 5 nm and about 300 nm in 1 nm increments, and is formed over a portion of the emitter layer 48. It is desirable to form the contact 50 to have a thickness of about 100 nm.
The contact layer 52, is formed from an InxGa1-x(As1-ySby) (0<x<0.7) (0<y<0.5) material doped with N type impurities in a high concentration in excess of 1×1019 cm-3. The contact layer 52 is desirably formed to have a thickness of between about 30 nm and about 150 nm in 1 nm increments. The contact layer 52 is formed over a portion of the contact 50.
The contact layer 52 formed from the InxGa1-x(As1-ySby) (0<x<0.7) (0<y<0.5)) material and the contact 50 formed of the InP material provides a significant reduction in an emitter resistance value. The minimal conduction band offset or discontinuity between the InxGa1-x(As1-ySby) (0<x<0.7) (0<y<0.5) material and the InP material that form the contact portion of the HBT 40 allow the emitter portion of the HBT 40 to realize a significant reduction in an emitter resistance value. For example, the emitter of the HBT 40 realizes an emitter resistance value of about 3 ohms to about 7 ohms (L=2×2 um2). The contact portion of the HBT 40 can be doped with a variety of n-type dopants, for example, silicon, tellurium, sulfur, tin, or selenium Moreover, the use of indium in the contact portion of the HBT 40 provides an increase in the electron mobility, which, in turn, provides a reduction in the resistance value associated with the emitter portion of the HBT 40. As such, the HBT 40 is well suited for use in or as a high speed multiplexer or in a high speed clock or data recovery circuit.
Those skilled in art will appreciate that the applications of the various compound semiconductor devices described herein are not limited solely to high speed data manipulation, for example, the compound semiconductor devices of the present invention are well suited for operations portable or mobile electronic devices capable of communicating with a network in a wireless manner to increase or improve the bandwidth capacity of the network. One possible example for the compound semiconductor devices of the present invention is the use in a mobile telephone or "cellphone" capable of communicating with a satellite network, a terrestrial network or a hybrid network of terrestrial network entities and satellite network entities.
While the present invention has been described with reference to illustrative embodiments thereof, those skilled in the art will appreciate that various changes in form in detail may be made without parting from the intended scope of the present invention as defined in the appended claims.
| Patent | Priority | Assignee | Title |
| 10052066, | Mar 30 2012 | The Board of Trustees of the University of Illinois | Appendage mountable electronic devices conformable to surfaces |
| 10056340, | May 31 2013 | HRL Laboratories, LLC | Flexible electronic circuit and method for manufacturing same |
| 10064269, | Mar 05 2008 | The Board of Trustees of the University of Illinois | Stretchable and foldable electronic devices |
| 10147809, | Jul 10 2013 | Murata Manufacturing Co., Ltd. | Semiconductor device |
| 10170602, | Feb 17 2016 | Qorvo US, Inc. | Semiconductor device with multiple HBTs having different emitter ballast resistances |
| 10204864, | Jun 04 2004 | The Board of Trustees of the University of Illinois | Stretchable form of single crystal silicon for high performance electronics on rubber substrates |
| 10292261, | Mar 05 2008 | The Board of Trustees of the University of Illinois; Northwestern University | Stretchable and foldable electronic devices |
| 10349860, | Jun 03 2011 | The Board of Trustees of the University of Illinois; The Trustees of the University of Pennsylvania | Conformable actively multiplexed high-density surface electrode array for brain interfacing |
| 10357201, | Mar 30 2012 | The Board of Trustees of the University of Illinois | Appendage mountable electronic devices conformable to surfaces |
| 10361180, | Jan 17 2007 | X Display Company Technology Limited | Optical systems fabricated by printing-based assembly |
| 10374072, | Jun 04 2004 | The Board of Trustees of the University of Illinois | Methods and devices for fabricating and assembling printable semiconductor elements |
| 10396173, | Dec 01 2011 | The Board of Trustees of the University of Illinois; Trustees of Tufts College | Transient devices designed to undergo programmable transformations |
| 10418468, | Feb 17 2016 | Qorvo US, Inc. | Semiconductor device with multiple HBTS having different emitter ballast resistances |
| 10424572, | Jan 17 2007 | X Display Company Technology Limited | Optical systems fabricated by printing-based assembly |
| 10441185, | Dec 16 2009 | The Board of Trustees of the University of Illinois | Flexible and stretchable electronic systems for epidermal electronics |
| 10504882, | Jan 17 2007 | X Display Company Technology Limited | Optical systems fabricated by printing-based assembly |
| 10546841, | May 12 2009 | The Board of Trustees of the University of Illinois | Printed assemblies of ultrathin, microscale inorganic light emitting diodes for deformable and semitransparent displays |
| 10629711, | Feb 17 2016 | Qorvo US, Inc. | Semiconductor device with multiple HBTs having different emitter ballast resistances |
| 10636897, | Jul 10 2013 | Murata Manufacturing Co., Ltd. | Semiconductor device having a collector layer including first-conductivity-type semiconductor layers |
| 10918298, | Dec 16 2009 | The Trustees of the University of Pennsylvania | High-speed, high-resolution electrophysiology in-vivo using conformal electronics |
| 10925543, | Nov 11 2015 | The Board of Trustees of the University of Illinois | Bioresorbable silicon electronics for transient implants |
| 11029198, | Jun 01 2015 | The Board of Trustees of the University of Illinois | Alternative approach for UV sensing |
| 11057991, | Dec 16 2009 | The Board of Trustees of the University of Illinois; Trustees of Tufts College | Waterproof stretchable optoelectronics |
| 11088268, | Jun 04 2004 | The Board of Trustees of the University of Illinois | Methods and devices for fabricating and assembling printable semiconductor elements |
| 11118965, | Jun 01 2015 | The Board of Trustees of the University of Illinois | Miniaturized electronic systems with wireless power and near-field communication capabilities |
| 11309305, | Jan 17 2007 | X Display Company Technology Limited | Optical systems fabricated by printing-based assembly |
| 11456258, | Jun 04 2004 | The Board of Trustees of the University of Illinois | Stretchable form of single crystal silicon for high performance electronics on rubber substrates |
| 6917061, | Jul 20 2001 | MICROLINK DEVICES, INC | AlGaAs or InGaP low turn-on voltage GaAs-based heterojunction bipolar transistor |
| 7576409, | Aug 20 2004 | HRL Laboratories, LLC | Group III-V compound semiconductor based heterojuncton bipolar transistors with various collector profiles on a common wafer |
| 7655529, | Aug 20 2004 | HRL Laboratories, LLC | InP based heterojunction bipolar transistors with emitter-up and emitter-down profiles on a common wafer |
| 7932123, | Sep 20 2006 | The Board of Trustees of the University of Illinois | Release strategies for making transferable semiconductor structures, devices and device components |
| 7972875, | Jan 17 2007 | X Display Company Technology Limited | Optical systems fabricated by printing-based assembly |
| 7982296, | Jun 04 2004 | The Board of Trustees of the University of Illinois | Methods and devices for fabricating and assembling printable semiconductor elements |
| 8039847, | Jun 04 2004 | The Board of Trustees of the University of Illinois | Printable semiconductor structures and related methods of making and assembling |
| 8097926, | Oct 07 2008 | MEDIDATA SOLUTIONS, INC | Systems, methods, and devices having stretchable integrated circuitry for sensing and delivering therapy |
| 8198621, | Jun 04 2004 | The Board of Trustees of the University of Illinois | Stretchable form of single crystal silicon for high performance electronics on rubber substrates |
| 8216910, | Aug 20 2004 | HRL Laboratories, LLC | Group III-V compound semiconductor based heterojunction bipolar transistors with various collector profiles on a common wafer |
| 8372726, | Oct 07 2008 | MEDIDATA SOLUTIONS, INC | Methods and applications of non-planar imaging arrays |
| 8389862, | Oct 07 2008 | MEDIDATA SOLUTIONS, INC | Extremely stretchable electronics |
| 8394706, | Jun 04 2004 | The Board of Trustees of the University of Illinois | Printable semiconductor structures and related methods of making and assembling |
| 8440546, | Jun 04 2004 | The Board of Trustees of the University of Illinois | Methods and devices for fabricating and assembling printable semiconductor elements |
| 8450162, | Feb 07 2007 | MicroLink Devices, Inc. | HBT and field effect transistor integration |
| 8470701, | Apr 03 2008 | X Display Company Technology Limited | Printable, flexible and stretchable diamond for thermal management |
| 8536667, | Oct 07 2008 | MEDIDATA SOLUTIONS, INC | Systems, methods, and devices having stretchable integrated circuitry for sensing and delivering therapy |
| 8552299, | Mar 05 2008 | The Board of Trustees of the University of Illinois | Stretchable and foldable electronic devices |
| 8664699, | Jun 04 2004 | The Board of Trustees of the University of Illinois | Methods and devices for fabricating and assembling printable semiconductor elements |
| 8666471, | Mar 17 2010 | Trustees of Tufts College | Implantable biomedical devices on bioresorbable substrates |
| 8697532, | Feb 07 2005 | HRL Laboratories, LLC | InP based heterojunction bipolar transistors with emitter-up and emitter-down profiles on a common wafer |
| 8722458, | Jan 17 2007 | X Display Company Technology Limited | Optical systems fabricated by printing-based assembly |
| 8754396, | Jun 04 2004 | The Board of Trustees of the University of Illinois | Stretchable form of single crystal silicon for high performance electronics on rubber substrates |
| 8865489, | May 12 2009 | The Board of Trustees of the University of Illinois | Printed assemblies of ultrathin, microscale inorganic light emitting diodes for deformable and semitransparent displays |
| 8886334, | Oct 07 2008 | MEDIDATA SOLUTIONS, INC | Systems, methods, and devices using stretchable or flexible electronics for medical applications |
| 8895406, | Sep 20 2006 | The Board of Trustees of the University of Illinois | Release strategies for making transferable semiconductor structures, devices and device components |
| 8905772, | Mar 05 2008 | The Board of Trustees of the University of Illinois | Stretchable and foldable electronic devices |
| 8934965, | Jun 03 2011 | The Board of Trustees of the University of Illinois | Conformable actively multiplexed high-density surface electrode array for brain interfacing |
| 9012784, | Oct 07 2008 | MEDIDATA SOLUTIONS, INC | Extremely stretchable electronics |
| 9105555, | Jun 04 2004 | The Board of Trustees of the University of Illinois | Stretchable form of single crystal silicon for high performance electronics on rubber substrates |
| 9117940, | Jan 17 2007 | X Display Company Technology Limited | Optical systems fabricated by printing-based assembly |
| 9159635, | May 27 2011 | MEDIDATA SOLUTIONS, INC | Flexible electronic structure |
| 9171794, | Oct 09 2012 | MEDIDATA SOLUTIONS, INC | Embedding thin chips in polymer |
| 9289132, | Oct 07 2008 | MEDIDATA SOLUTIONS, INC | Catheter balloon having stretchable integrated circuitry and sensor array |
| 9349900, | Sep 20 2006 | The Board of Trustees of the University of Illinois | Release strategies for making transferable semiconductor structures, devices and device components |
| 9442285, | Jan 14 2011 | The Board of Trustees of the University of Illinois | Optical component array having adjustable curvature |
| 9450043, | Jun 04 2004 | The Board of Trustees of the University of Illinois | Methods and devices for fabricating and assembling printable semiconductor elements |
| 9515025, | Jun 04 2004 | The Board of Trustees of the University of Illinois | Stretchable form of single crystal silicon for high performance electronics on rubber substrates |
| 9516758, | Oct 07 2008 | MEDIDATA SOLUTIONS, INC | Extremely stretchable electronics |
| 9530708, | May 31 2013 | HRL Laboratories, LLC | Flexible electronic circuit and method for manufacturing same |
| 9554484, | Mar 30 2012 | The Board of Trustees of the University of Illinois | Appendage mountable electronic devices conformable to surfaces |
| 9601671, | Jan 17 2007 | X Display Company Technology Limited | Optical systems fabricated by printing-based assembly |
| 9647171, | May 12 2009 | The Board of Trustees of the University of Illinois | Printed assemblies of ultrathin, microscale inorganic light emitting diodes for deformable and semitransparent displays |
| 9691873, | Dec 01 2011 | The Board of Trustees of the University of Illinois | Transient devices designed to undergo programmable transformations |
| 9723122, | Oct 01 2009 | MEDIDATA SOLUTIONS, INC | Protective cases with integrated electronics |
| 9761444, | Jun 04 2004 | The Board of Trustees of the University of Illinois | Methods and devices for fabricating and assembling printable semiconductor elements |
| 9765934, | May 16 2011 | Northwestern University | Thermally managed LED arrays assembled by printing |
| 9768086, | Jun 04 2004 | The Board of Trustees of the University of Illinois | Methods and devices for fabricating and assembling printable semiconductor elements |
| 9905678, | Feb 17 2016 | Qorvo US, Inc. | Semiconductor device with multiple HBTs having different emitter ballast resistances |
| 9936574, | Dec 16 2009 | Trustees of Tufts College | Waterproof stretchable optoelectronics |
| 9986924, | Mar 17 2010 | The Board of Trustees of the University of Illinois; Northwestern University; Trustees of Tufts College; The Trustees of the University of Pennsylvania | Implantable biomedical devices on bioresorbable substrates |
| Patent | Priority | Assignee | Title |
| 6043520, | Apr 02 1998 | MURATA MANUFACTURING CO , LTD | III-V heterojunction bipolar transistor having a GaAs emitter ballast |
| 20020190273, |
| Executed on | Assignor | Assignee | Conveyance | Frame | Reel | Doc |
| Jul 22 2002 | MicroLink Devices, Inc. | (assignment on the face of the patent) | / | |||
| Sep 13 2002 | PAN, NOREN | MICROLINK DEVICES, INC | ASSIGNMENT OF ASSIGNORS INTEREST SEE DOCUMENT FOR DETAILS | 013404 | /0139 | |
| Sep 23 2002 | HAN, BYUNG-KWON | MICROLINK DEVICES, INC | ASSIGNMENT OF ASSIGNORS INTEREST SEE DOCUMENT FOR DETAILS | 013404 | /0139 | |
| Jan 30 2012 | MICROLINK DEVICES, INC | PNC Bank, National Association | SECURITY AGREEMENT | 027853 | /0736 | |
| Aug 18 2016 | PNC BANK NATIONAL ASSOCIATION | MICROLINK DEVICES, INC | RELEASE BY SECURED PARTY SEE DOCUMENT FOR DETAILS | 039482 | /0650 |
| Date | Maintenance Fee Events |
| Jun 11 2007 | M2551: Payment of Maintenance Fee, 4th Yr, Small Entity. |
| Jun 09 2011 | M2552: Payment of Maintenance Fee, 8th Yr, Small Entity. |
| Jun 09 2015 | M2553: Payment of Maintenance Fee, 12th Yr, Small Entity. |
| Date | Maintenance Schedule |
| Dec 09 2006 | 4 years fee payment window open |
| Jun 09 2007 | 6 months grace period start (w surcharge) |
| Dec 09 2007 | patent expiry (for year 4) |
| Dec 09 2009 | 2 years to revive unintentionally abandoned end. (for year 4) |
| Dec 09 2010 | 8 years fee payment window open |
| Jun 09 2011 | 6 months grace period start (w surcharge) |
| Dec 09 2011 | patent expiry (for year 8) |
| Dec 09 2013 | 2 years to revive unintentionally abandoned end. (for year 8) |
| Dec 09 2014 | 12 years fee payment window open |
| Jun 09 2015 | 6 months grace period start (w surcharge) |
| Dec 09 2015 | patent expiry (for year 12) |
| Dec 09 2017 | 2 years to revive unintentionally abandoned end. (for year 12) |